Embattled Metropolitan Police chief Sir Bernard Hogan-Howe will be grilled by MPs this week over bombshell claims that Scotland Yard and the Crown Prosecution Service were involved in a ‘deliberate cover-up’ of damning evidence of police corruption.

A court was told that the Met and the CPS repeatedly concealed documents suggesting that officers investigating a billionaire Nigerian politician for fraud were paid to leak details of the inquiry that could have helped him evade justice. One detective was said to have received at least 19 unexplained cash deposits totalling thousands of pounds into his bank account, after illegally disclosing sensitive information, a judge heard.

But when the corruption allegations were revealed by a whistle-blowing lawyer, the lawyer was accused of forging the evidence, and charged with perverting the course of justice. Police privately expressed fears that his devastating claims could undermine the £50million fraud trial.

Last month the charges against the solicitor were dramatically dropped after the CPS was forced to produce crucial papers, which it had always insisted did not exist, that suggest serving Met officers took bribes.

Although the Met insists no corruption took place, the case leaves the Met Commissioner – already under fire over his refusal to apologise for the Yard’s disastrous historical sex abuse investigations – facing difficult questions from the Home Affairs Select Committee next week, as he was personally warned about the potential miscarriage of justice three years ago.

The CPS’s handling of the case, criticised by former police as well as the defendants, will also increase pressure on Director of Public Prosecutions Alison Saunders, who faced calls to quit over her failure to put Lord Janner on trial.

As the full astonishing story is told for the first time, it can also be revealed that a Met Commander, Peter Spindler, who reported directly to Sir Bernard, told the BBC the corruption claims were bogus without having checked if documents were genuine.

Last night the lawyer who had been accused of forgery, Bhadresh Gohil, told The Mail on Sunday: ‘I uncovered serious corruption, but when I tried to expose this, I was victimised. Astonishingly, the CPS used the might of the state and all its resources to cover up what had happened, and brought trumped-up charges to persecute me. The truth has finally unravelled.’

MP Keith Vaz, chairman of the Home Affairs Committee, said: ‘Members have indicated they will want to ask the Commissioner, when he next appears before the committee, to deal with the latest developments which raise a number of new questions.’

The extraordinary case centres on Scotland Yard’s prosecution of James Ibori, who once worked as a cashier at a branch of Wickes DIY store in West London before returning to his native Nigeria to enter politics and become one of Africa’s richest men as governor of oil-rich Delta State. He was jailed for 13 years in 2012 at Southwark Crown Court after admitting fraud and money-laundering following the Met investigation into his vast wealth, with the court hearing that he siphoned off public cash to live a ‘lavish lifestyle’, enjoying a private jet, homes in Hampstead and Regents Park, armoured cars and places at top British boarding schools for his children.

Gohil, who was Ibori’s business lawyer, was also jailed for seven years after admitting fraud, although he claims he was wrongly advised to do so by his then legal team. He was separately found guilty of money-laundering – a charge he continues to deny.

“The investigation by the Department of Professional Standards into Mr Gohil’s allegations of corruption was a whitewash and was deliberately designed to find that no corruption of the type Mr Gohil had complained about existed… it was designed to fail. ”